PARIS -- U.S. President Donald Trump is under fire for treating U.S.-Mexico border-hoppers like lawbreakers, even though they're literally breaking the law. As with any crime, when parents are detained in prison, children don't go with them. The resulting optics are not pretty.

It would be much better if the border were simply sealed, would-be hoppers turned back along with their children, and requests for asylum submitted from outside the United States. Instead, Trump's critics are using the optics as leverage to attack Trump's attempt to secure the border.

Mexico currently has the same U.S. State Department travel advisory level as France, so sending someone back to Mexico isn't exactly inhumane. Yet we've gotten to the point where it's considered inhumane and unacceptable not to let everyone in, particularly if there are kids involved.

Western immigration policy has long been vulnerable to emotional blackmail. Remember how the image of a Syrian migrant child washed ashore in Turkey became a pretext for demanding that the floodgates be opened in Europe and the United States?

If you don't have clear boundaries in life that you're willing to defend even when faced with mounting pressure, someone is bound to exploit them: a partner, a boss, a human trafficker. What do we call people without defined boundaries in life? Insecure. It's the same with countries.

Hey, America, I've seen your future if you go down this road. I can tell you exactly how it's going to turn out -- and it's the opposite of what leftists might be imagining.

Here in Europe, the interior minister of Italy's new populist anti-immigration government, Matteo Salvini, has closed the country's ports to nongovernmental organization rescue ships carrying migrants who were abandoned by human traffickers. A recent poll showed that 59 percent of Italians agree with the move.

"They should know that Italy no longer wants to be an accomplice in the business of illegal immigration," Salvini said.

Anything short of blocking all illegal immigration at the U.S. border only serves to fuel the same sort of trafficking activities. The bleeding hearts swayed by images of children are exacerbating the problem by defending the viability of the traffickers' business model.

Leftism is ultimately inhumane. Not only is it enabling human trafficking, but it's also at the crux of why mass migration exists in the first place: The left's war on poverty has been an abysmal failure.

Attempts to redistribute wealth from developed nations to underdeveloped nations have been a disaster. If anything, foreign aid has fomented more chaos inside underdeveloped countries than it has resolved.

For example, the U.S. Agency for International Development, which manages billions of dollars in U.S. humanitarian aid, launched a Twitter-like social network called ZunZuneo in Cuba in a veiled attempt to undermine the Cuban government and sow the seeds of democracy in a communist country. The service was shut down after just two years.

Throwing money at a problem and proclaiming that something is being accomplished doesn't make it so. But it's easier to go that route than to make hard but effective decisions that are portrayed in the media as cruel. The backlash against the Trump administration for its hardline border policy is something we've already lived through here in Europe.

Roughly a decade ago, former French President Nicolas Sarkozy was criticized for tackling lax border security and ordering deportations. At that point, the French still had the luxury of criticism. Insecurity and social discord grew worse under Sarkozy's Socialist successor, Francois Hollande, whose term was marred by several major terrorist attacks. The result was inevitable: The National Front's anti-immigration platform scored it a spot in the runoff of last year's presidential election, despite incessant attacks in the media.

The far right is now surging across Europe -- in countries such as Italy, Germany, Slovenia, Poland, Austria, Hungary and France -- while the left is on the downswing. The discrepancy between the utopian, open-borders view of the world that is promoted by much of the European media is increasingly at odds with the viewpoint of average citizens, as evidenced by the results of recent elections.

Mass migration and attempts at integration have failed here in Europe. People have simply had enough. They can no longer be manipulated by accusations of heartlessness in the interests of keeping the borders open.

As America and Canada now face an onslaught of foreign migrants attempting to enter illegally under humanitarian pretext, these governments still have the luxury of choosing to close the door before voters make that choice for them.